Thi tốt môn tiếng Anh trong kỳ thi tuyển sinh Đại học - Cao đẳng sắp tới với tài liệu tham khảo đề thi thử Đại học môn tiếng Anh khối D. Với tài liệu này các bạn sẽ được cung cấp những câu hỏi trắc nghiệm hay và hữu ích nhất. | Any change in one part of an ecosystem can cause changes in other parts. Droughts, storms and fires can change ecosystems. Some changes _71 ecosystems. If there is too _72 rainfall, plants will not have enough water to live. If a kind of plant dies off, the animals that _73 it may also die or move away. Some changes are good for ecosystems. Some pine forests need _74 for the pine trees to reproduce. The seeds are sealed inside pinecones. Heat from a forest fire melts the seal and lets the seeds _75. Polluting the air, soil, and water can harm ecosystems. Building _76 on rivers for electric power and irrigation can harm ecosystems _77 the rivers. Bulldozing wetlands and cutting down 78_ destroy ecosystems. Ecologists are working with companies and governments to find better ways of 79_ fish, cutting down trees, and building dams. They are looking for ways to get food, lumber, and other products for people _80 causing harm to ecosystems.
